Burglar-alarm



(No Model.)

P. W. PEARSON 8:; A. M. EASTMAN.

BURGLAR ALARM.

No. 249,982. Patented Nov. 22,1881.

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1 PETERS. Fhnlohlhogmpher. Washington D. C.

UNITED TaTns PATENT Trice.

FRANCIS W. PEARSON, F BOSTON, AND ANDRE\V M. EASTMAN, OF SOMER- VILLE, ASSIGNORS, BY DIRECT AND MESNE ASSIGNMENTS, TO ALBERT D. S. BELL, TRUSTEE, OF NEWTON, MASSACHUSETTS.

BU RGLAR-ALARIVI.

SPECIFICATION forming part of Letters Patent No. 249,982, dated November 22, 1881,

Application filedJnly13,1881. (No model.) i

To all whom it may concern:

Be it known that we, FRANCIS W. PEAR- soN and ANDREW M. EASTMAN, both citizens of the United States, residing, the former at Boston, in the county of Suffolk and State of Massachusetts, and the latter at Solnerville, in the countyot' Middlescx and State of Massachusetts, have jointly invented certain new and useful Improvements in Alarm-Bells and Door-Knobs; and we do hereby declare that the same are fully described in the following specification and illustrated in the accompany ing drawings.

This invention relates to improvements on the patent granted to F. N. Oottle, March 25,

1879, No. 213,547, for alarm-bell and doorknobs; and it consists of an improvement in the striker mechanism of the hollow bell doorknob, the invention being carried out as fol- 2o lows, reference being had to the accompanying drawings, in which Figure 1 representsa longitudinal section of the device as applied to a door. Fig. 2 represents an end view of the interior mechanism with the alarm-bell shown as removed; and Fig. 3 represents a cross-section on the line A B, shown in Fig. 1.

Similar letters refer to similar parts wherever they occur on the different parts of the 0 drawings. j

(t represents the door, with its ldck i), outer knob or handle, 0, and door spindle cl, in the usual manner.

0 is the hollow shank of the knob c, on the 5 inside of which the striker mechanism is located, as will hereinafter be described. The shank e is secured to the spindle d by means of the pin f, as shown in Figs. 1 and 3.

g is the hollow bellknob, withits central 4o shank, g, inserted into the central perforation of thehollow shank c, to which it is secured by means of the set-screw h, as shown in Fig. 1.

'i is the knob-rose, secured to the inside of the door a, as shown, the central perforation 5 of which knob-rose serves as a bearing for the inner end of the hollow shank e. The knobrose 1; is provided on its rim with a recess or opening, i, bounded by cam faces i i, as

shown in Fig.3. Within the recess iisloosely restingthe lower bent end, 7c, of the lever 70, as shown in Fig. 1. The lever 70 has another bend,k,inits upper end,projecting up through the duplex curved cam-groove l in the laterally-adjustable latch-plate Z, that is provided with a projecting lip, 1, that actuates a similar projection, m, on the ham mer-lever 122 when either of the knobs c or g is turned on their common axis to open the door, which hammerlever is released from the latch-plate l before the doorlock is wholly withdrawn, when its hammer m is automatically caused to strike against the inside of the bell-knob g by the influence of the coiled spring 42, attached in one end to the bentend m of said hammer-lever m, and in its other end to the screw 0, secured to the knob e. I

To properly guide the latch-plate l in its forward-and-back motion it is provided in one end with a straight slot, 1), embracing the stationary guide-screwp, secured to the knob e, and in its other end, nearest to thelip l, with a curved cam-slot, q, embracing the stationary guide-screw q, also secured to the knob c, as shown in Fig. 2. As soon as either of the knobs g ore is released thelatoh-plate lis auto- 7 5 matically moved to its normal position (shown in Fig. 2) by the influence of the spring r, secured in one end to the set-screw 0, and having its free end acting on the projection s on the'latch-plate l, as shown in Fig. 2. By this arrangementthehammer m is caused to strike against the inside of the bell knob g, when either of the knobs c or g isturned previous to the complete release of the doorlock, producing a clear alarm when the outer knob, c, is 8 grasped, and a muffled sound by grasping the inner knob, g.

If it is desired to open thedoor without cansing the hammer to strike, it is only necessary to slide the bent lever is toward the gong 9, so that the lower end, It, of said lever is moved out of the recess 2" on theknob-rose i, for which purpose said lower end, it, may be provided with teeth or notches t, as shown in Fig.1, or a projecting pin or equivalent device, as may 5 be desired. If it is desired to connect the alarm, it is only necessary to slide the lower end, k, of said lever into the recess z" to the position as shown in Fig. 1. By turning the spindle d, either by grasping the knob c or the knob g, the lever It raises the slotted latchplate lp q, on accountot'its lowerend, k,resting in the slot i in the knob-rose i, and when so turned its upper end, 7;, that projects through the duplex slot 1 causes the latchplate I and its projection l to act on the lip m on the hammer-lever m, and as the latchplate I is guided toward the right by means of the guide qand curved slot q, the projection l is made to pass by the lip m on the hammerlever m, releasing the latter and causing its hammer m to strike the inside of the gong g by the influenceot' the spring n. By releasing the grasp on either of the knobs c or g the latch-plate l is automatically moved toits normal position, as shown in Fig. 2, by the infiuence of the spring 1', acting on the projection 8.

Having thus fullydescribed the nature, construction, and operation of the invention, we desire to secure by Letters Patent, and claim- The herein-described improved alarm mechanism, consisting of the handles 0 and a, shank e, spindle d, knob-rose 17, its recess t" and camfaces t' i, bent lever k 70 k, slotted latchplate 1p q, guides 11 q, projection l, camgroove l, the.hamn1er m m m, and springs n 1', as and for the purpose set forth.

In testimony whereof we have afiixed our signatures in presence of two witnesses.

FRANCIS WV. PEARSON. ANDREW M. EASTMAN.

l Vitnesses:

HANNAH P. EASTMAN, ALBAN ANDRI JN. 

